Method of forming a boiler head or the like



Nov. 11, 1958 J. F. BAXA 2,859,510

METHOD OF FORMING A BOILER HEAD OR THE LIKE Original Filed Jan. 13, 19555 Sheets-Sheet 1 Q Q oo Z N (D INVENTORY JAMES F. BAXA as ATTORNEY Nov.11, 1958 J. F. BAXA 2,859,510

METHOD OF FORMING A BOILER HEAD OR THE LIKE Original Filed Jan. 13 19555 Sheets-Sheet 2 INVENTOR JAMES F. BAXA 24 mg, QLQ/ HIS ATTORNEYS Nov.11, 1958 ,J. F; BAXA 2,859,510

METHOD OF FORMING A BOILER HEAD OR THE LIKE Original Filed Jan. 15, 19555 Sheets-Sheet 5 Fls.6g

Fi e. 5

INVENTOR JAMES F. BAXA HIS A TTORNEYS United state METHOD or FonMrNn ABOILER HEAD on THE LHQE Griginal application January 13,1955 Serial No.481,616. giguzlgg and this application July 15, 1955, Serial No.

4 Claims. (Cl. 29-1514) This invention relates to a method of forming aboiler head or the like. This application is a division of my copendingapplication Serial No. 481,616, filed January 13, 1955, abandoned sincefiling of this application.

The invention has to do with the forming of articles such as boilerheads having an opening therethrough and a tubular projection integralwith the article coaxial with the opening for receiving closure means.The closure means may be a threaded plug and the tubular projection maybe threaded to receive the plug. For purposes of explanation andillustration the invention will be described as embodied in a boilerhead and as practiced in the forming of a boiler head.

The tubular projection may be subjected to heavy stress, especially whenthe boiler of which the head is a part contains fluid under pressure. Ithas heretofore been recognized that the wall thickness of the tubularprojection should be as great as the specified wall thickness of theboiler head surrounding the tubular projection. To obtain that resultseparate spuds have been utilized but the cost incident to the provisionand attachment of separate spuds is substantial. To avoid that cost ithas been proposed to form the tubular projection integral with thematerial of the head. This has been done by both hot and cold formingbut the result prior to the present invention has been a tubularprojection of less wall thickness than the head at at least asubstantial portion of the tubular projection. Since the wall thicknessof the tubular projection should be as great as the wall thickness ofthe head itself which is required to withstand the pressure within theboiler those skilled in the art have been utilizing metal ofunnecessarily great thickness for the heads of boilers in order to formintegral tubular projections having the necessary wall thickness towithstand the imposed stresses. This has entailed undesirable expensethrough the utilization of heads which are heavier than required notonly in the cost of the material of the head but also in increasedshipping charges because of the increased Weight of the boiler.

I have solved the problem by producing a boiler head or the like havinga tubular projection integral with the metal of the head and whose wallthickness is at least as great as the thickness of the material of thehead. Specifically, I provide a boiler head or the like comprising aplate-like metal member having an opening therethrough and a tubularprojection integral with the platelike metal member and projectinggenerally normal thereto, the inner surface of the tubular projectionbeing continuous with the periphery of the opening, the thickness of themetal forming the tubular projection being at least as great as thethickness of the metal of the platelike metal member surrounding thetubular projection. Desirably the tubular projection gradually increasesin transverse dimension from one end to the other thereof to adapt it toreceive a tapered plug. Normally the tubular projection is threaded. Ifit is to receive a tapered externally threaded closure plug the tubularprojection should be of greater transverse dimension at its outer atentice extremity than at its inner extremity and should be internallythreaded to receive the tapered plug. If the tubular projection is toreceive an internally threaded closure cap it should be externallythreaded. The most common type of closure is a tapered externallythreaded closure plug so that normally the tubular projection will beshaped to receive such a plug and internally threaded. The tubularprojection may project in either direction from the boiler head.

I preferably form a boiler head or the like by hot die-forming aplate-like metal member having an opening therethrough to enlarge theopening and form a tubular projection integral with the plate-like metalmember and projecting generally normal thereto whose inner surface iscontinuous with the periphery of the opening but with the thickness ofthe metal forming the tubular projection being at least a portion of thetubular projection less than the thickness of the metal of theplate-like metal member surrounding the tubular projection and upsettingthe metal of the tubular projection to increase the thickness of themetal thereof at said portion thereof to a thickness at least as greatas the thickness of the metal of the plate-like metal member surroundingthe tubular projection. I preferably shape the tubular projection sothat it gradually increases in transverse dimension from one end to theother thereof, and I preferably thread the tubular projection. Otherdetails, objects and advantages of the invention will become apparent asthe following description of a present preferred method of practicingthe same proceeds.

In the accompanying drawings I have illustrated a present preferredmethod of practicing the invention in which Figure 1 is across-sectional view through apparatus for forming a boiler head andillustrating the first step of my improved method;

Figures 2, 3 and 4-are views similar to Figure 1, illus-, tratingsucceeding steps of my improved method;

Figures 5 and 6 are cross-sectional views through ap paratus for shapingthe tubular projection so that it grad ually increases in transversedimension from one end to the other thereof; and

Figure 7 is a fragmentary cross-sectional view through a finished boilerhead.

My boiler head or the like may be of conventional shape and adapted tobe applied to a boiler shell in conventional manner but it may be madeout of metal of v thinner gauge than has heretofore been required forthe manufacture of boiler heads with integral tubular projections tomeet particular specifications because the tubular projection which Iform integral with the head has at least as great wall thickness at thehead. Indeed, I may form a tubular projection integral with a boilerhead or the like having even greater wall thickness than the head or thelike if for any reason such a structure should be desired.

Figures 1 to 4, inclusive, show one form or my.ap-. paratus for forminga boiler head or the like and illus trate my method. The apparatuscomprises a base member 2 which is mounted in fixed position. The basemember 2 carries an upsetting die 3 which is upwardly open and ofannular shape as shown. The upsetting die is carried by the base memberin fixed position.

A plurality of bores 4 are drilled through the base member 2, only onesuch bore being shown in the drawing for simplicity of illustration.surround the upsetting die 3 and are uniformly spaced. Projectingupwardly through each of the bores 4 is a pin 5 which is resilientlyforced upwardly, as, for example, by fluid under pressure. The lowerextremity of each pin 5 may carry a piston (not shown) operating in afluid pressure cylinder. When fluid under pressure is employed The bores44 preferably I prefer to employ air as the fluid under pressure buthydraulic fluid may be employed if desired.

The pins 5 resiliently support a die member 6 having extendingtherethrough a die cavity 7 snugly receiving the upsetting die 3 asshown. The die member 6 is adapted to move axially of the upsetting die3 against the fluid pressure exerted against the pins 5 as willpresently be described and may be guided in such movement by theupsetting die 3 alone, or other guide means for insuring properly guidedmovement of the die member 6 relatively to the base member 2 may beprovided. Means not shown limit the upward movement of the die memher 6,that member being shown in its extreme upper position in Figures 1 and2, being maintained in that position by the pins 5.

A blank 8 is adapted to be supported upon the die member 6. The blank 8may be a boiler head or the like on which an integral tubular projectionis to be formed. The blank 8 may have a wall thickness no greater thanthe wall thickness required by the boiler specifications. It ispredrilled to form therethrough an opening 9. The blank 8 is preheatedto the proper temperature for hot forging the particular metal beingemployed, which may, for example, be a grade of carbon steel appropriatefor forming boiler heads.

The blank 8 is maintained in position upon the die member 6 with theopening 9 coaxial with the die cavity 7 by a holding member 10. Theholding member 10 has therein an opening 11 of somewhat smallertransverse dimension than the die cavity 7 coaxial with the die cavity7. The die cavity 7, the openings 9 and,11 and the upsetting die 3, aswell as the punch presently to be described, may be of circular crosssection although they may also be of other cross section so long as theyare designed to conform with one another. In the present illustrationthey will be assumed to be of circular cross section.

I provide a punch designated generally by reference numeral 12comprising a holder portion 13 and a punch member 14. The punch member14 is adapted to pass through the opening 11 in the holding member 10and has a pointed nose 15. The punch member 14 is coaxial with the diecavity 7. A series of compression coil springs indicateddiagrammatically at 16 are disposed about the punch member 14 forbiasing the punch relatively to the holding member 10.

At the beginning of a cycle of operations of the die mechanism shown inFigures 14 the punch and holding member 10 are retracted upwardly awayfrom the die member 6. The blank 8 is brought to the required heat andplaced upon the die member 6 as shown in Figure l with the opening 9coaxial with the die cavity 7. The holding member 10 is then broughtinto operative position to hold the blank 8 against the die member 6 asshown in Figure l. The holding member 10 is pressed against the blank 8by the springs 16 and may be guided in its movements toward and from thedie member 6 by guide means not shown but of a type known to thoseskilled in the art. The punch holder 13 may be similarly guided.

With the blank 8 held firmly in place against the die member 6 by theholding member 10 the punch is moved downwardly successively to thepositions of Figures 2 and 3. The tapered nose 15 of the punch member 14enters the opening 9 of the blank and enlarges that opening and thepunch hot die-forms the metal of the blank '8 at the periphery of theopening which projects radially inwardly of the periphery of the diecavity 7 as shown in Figures 2 and 3. It is inevitable that in suchdie-forming of the metal its wall thickness will be reduced. This isillustrated in the drawings.

When the punch 12 has reached the position shown in Figure 3 the springs16 are fully compressed and the portion 13 of the punch directly engagesthe holding member 10 and has started to move the holding member 10, theblank 8 and die member 6 downwardly up to a point just before theposition of the parts shown in Figure 3, the fluid pressure actingupwardly against the pins 5 has been sufiicient to hold the die member 6in the position shown in Figures 1 and 2. As the punch moves downwardlyit carries with it the holding member 10, the blank 8 and the die member6. Since the upsetting die 3 is fixedly mounted in the fixed base member2 the downward movement of the punch, holding member, blank and diemember causes the annular upsetting die to upset the material of thetubular projection formed on the blank between the punch member and thewall of the die cavity as shown in Figure 4.

' Thus I can form a tubular projection integral with a boiler head orthe like having at least as great wall thickneSs as the material of thehead and even greater wall thickness if desired. 1 eliminate thenecessity of either applying a separate spud or employing for the headmaterial of greater wall thickness than required by the boilerspecifications.

It would be possible to utilize the tubular projection formed as abovedescribed and as shown in Figure 4 for holding a closure member in placeto seal the boiler head, as, for example, by internally threading thetubular projection and screwing an externally threaded closure plugthereinto. However, it is preferred, and customary in the art, to taperthe tubular projection and internally thread it so that it is adapted toreceive a tapered externally threaded closure plug of conventionalconstruction. The tapering operation is shown in Figures 5 and 6. Theboiler head which has been hot die-formed as shown in Figures 1-4 andexplained above is further formed in tapering dies, the taperingoperation being performed either hot or cold.

There is provided a fixed base member 17 in which is mounted a femaletapering die 18 whose inner annular face 19 at the upper portion thereofviewing Figures 5 and 6 is tapered downwardly and inwardly as shown. Themouth or upper extremity of the die 18 has substantially the same shapeand transverse dimension as the outside of the tubular projection formedin Figures 1-4. The blank 8 after bein hot die-formed as illustrated inFigures 1-4 is transferred to the tapering dies of Figures 5 and 6, withor without a reheating, and is positioned relatively to the die 18 asshown in Figure 5.

Mounted above the die 18 for vertical movement in a guide 20 is anannular holddown member 21 in which operates a male tapering die 22having a downwardly and inwardly tapered nose 23 as shown.

While the die 22 remains stationary in the position shown in Figure 5the holddown member 21 moves downwardly and engages the upper surface ofthe blank 8 and forces it down against the die 18 with the tubularprojection entering the die 18 and being forced radially inwardly. Thenthe die 22 is lowered to the position shown in Figure 6, the tubularprojection on the blank 8 being reformed to the shape shown in Figure 6.The wall thickness of the tubular projection remains substantially thesame as formed in the operation shown in Figure 4, i. e., at least asgreat as the wall thickness of the blank 8 or greater if desired.

After the tapering operation of Figures 5 and 6 the tapered tubularprojection is internally threaded as shown at 24 in Figure 7. Thiscompletes the formation of the boiler head or the like. Not only is thetubular projection of at least as great wall thickness as the head butit is of constant wall thickness and there is no zone of Weakness due toreduced wall thickness in the finished wall such as has characterizedpreviously integrally formed tubular projections which prior to thepresent invention as above explained necessitated the employment ofmetal for the head having a wall thickness or gauge greater than thatrequired by the boiler specifications with the consequent disadvantagesabove pointed out.

The apparatus herein illustrated is claimed in my copending applicationSerial No. 629,673, filed December 20, 1956, which is a division of thisapplication.

While I have illustrated and described a present preferred method ofpracticing the invention it is to be distinctly understood that theinvention is not limited thereto but may be otherwise variously embodiedand practiced within the scope of the following claims.

I claim:

1. A method of forming a boiler head or the like comprising fixedlypositioning for hot die-forming a platelike metal member having anopening therethrough, while maintaining the plate-like metal member thusfixedly positioned hot die-forming the plate-like metal member toenlarge the opening and form a tubular projection integral with theplate-like metal member and projecting generally normal thereto whoseinner surface is continuous with the periphery of the opening but withthe thickness of the metal forming the tubular projection being at atleast a portion of the tubular projection less than the thickness of themetal of the plate-like metal member surrounding the tubular projectionand while continuing to maintain the plate-like metal member thusfixedly positioned upsetting the metal of the tubular projection toincrease the thickness of the metal thereof at said portion thereof to athickness at least as great as the thickness of the mteal of theplate-like metal member surrounding the tubular projection.

2. A method of forming a boiler head or the like comprising fixedlypositioning for hot die-forming a platelike metal member having anopening therethrough, while maintaining the plate-like metal member thusfixedly positioned hot die-forming the plate-like metal member toenlarge the opening and form a tubular projection integral with theplate-like metal member and projecting generally normal thereto whoseinner surface is continuous with the periphery of the opening but withthe thickness of the metal forming the tubular projection being at atleast a portion of the tubular projection less than the thickness of themetal of the plate-like metal member surrounding the tubular projection,while continuing to maintain the plate-like metal member thus fixedlypositioned upsetting the metal of the tubular projection to increase thethickness of the metal thereof at said portion thereof to a thickness atleast as great as the thickness of the metal of the plate-like metalmember surrounding the tubular projection and shaping the tubularprojection so that it gradually increases in transverse dimension fromone end to the other thereof.

3. A method of forming a boiler head or the like comprising fixedlypositioning for hot die-forming a plate-like metal member having anopening therethrough, while maintaining the plate-like metal member thusfixedly positioned hot die-forming the plate-like metal member toenlarge the opening and form a tubular projection integral with theplate-like metal member and projecting generally normal thereto whoseinner surface is continuous with the periphery of the opening but withthe thickness of the metal forming the tubular projection being at atleast a portion of the tubular projection less than the thickness of themetal of the plate-like metal member surrounding the tubular projection,while continuing to maintain the plate-like metal member thus fixedlypositioned upsetting the metal of the tubular projection to increase thethickness of the metal thereof at said portion thereof to a thickness atleast as great as the thickness of the metal of the plate-like metalmember surrounding the tubular projection, and threading the tubularprojection.

4. A method of forming a boiler head or the like comprising fixedlypositioning for hot die-forming a plate-like metal member having anopening therethrough, while maintaining the plate-like metal member thusfixedly positioned hot die-forming the plate-like metal member toenlarge the opening and form a tubular projection integral with theplate-like metal member and projecting generally normal thereto whoseinner surface is continuous with the periphery of the opening but withthe thickness of the metal forming the tubular projection being at atleast a portion of the tubular projection less than the thickness of themetal of the plate-like metal member surrounding the tubular projection,while continuing to maintain the plate-like metal member thus fixedlypositioned upsetting the metal of the tubular projection to increase thethickness of the metal thereof at said portion thereof to a thickness atleast as great as the thickness of the metal of the plate-like metalmember surrounding the tubular projection, shapingthe tubular projectionso that it gradually increases in transverse dimension from one end tothe other thereof and threading the tubular projection.

References Cited in the file of this patent UNITED STATES PATENTS1,137,600 Gallagher Apr. 27, 1915 1,246,456 Parpet Nov. 13, 19171,264,854 Possons Apr. 30, 1918 1,623,325 Wetmore Apr. 5, 1927 2,078,195Cornell, Jr Apr. 20, 1937 2,149,508 Coe Mar. 7, 1939 2,157,354 ShermanMay 9, 1939 2,168,641 Arbogast Aug. 8, 1939 2,373,901 Lowery Apr. 17,1945 UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No.2,859,510 November 11, 1958 James F. Baxa It is herebjr certified thaterror appears in the -printed specification of the above numbered patentrequiring correction and that the said Letters Patent should read ascorrected below.

Column 2, line 17, for "being at least" read being at at least line 51,for "at", second occurrence, read as line 56, for "form or" read form ofcolumn 5, line 26, for "mteal" read metal Signed and sealed this 3rd dayof March 1959.

SEAL) Attest:

KARL H. AXLINE ROBERT C. WATSON Attesting Oflicer Commissioner ofPatents

